What's the use of tool, 'Sort Elements'?
For almost all operations, there is no need to resort the geometry.

In a blender mesh, every vertex has index. The indices are usually set in the order, in which the vertices have been created.

I have created the vertices in this figure in this order.



Executing a short python script, we can confirm find out, that the actual indexed order is different. (When executing the following python scripts, toggle at least once into object mode to update the vertices property.)

import bpy

ob = bpy.context.object

# get x coordinates for every vertex
x = [v.co.x for v in ob.data.vertices]

print(x)
# &gt;&gt;&gt; [0.0, 2.0, -1.0, 1.0, -2.0]


This is the indexed order of the vertices.



However, when we select the vertices and execute Mesh > Sort Elements ... > View X Axis, the order has changed and the vertices are sorted.

&gt;&gt;&gt; [-2.0, -1.0, 0.0, 1.0, 2.0]




All operations (internal or scripted addons), which are dependant on the index, are affected when resorting the indices.

For example, I executed W > Randomize Vertices on two meshes. The right mesh has been sorted prior. The results are different.



Here is a gif to reproduce the example.